Maternal effect plays important role in adaptive evolution and population dynamics. Methylparaben (Mep) is a common organic pollutant exerting diverse impacts on aquatic organisms. However, the impact of maternal Mep exposure on offspring remains poorly understood. This study was designed to explore whether maternal Mep exposure can affect the offspring’s population performance, either by amictic mothers in parthenogenesis phase, or by mictic mothers in sexual reproduction phase of the rotifer Brachionus calyciflorus. Here, we exposed either amictic or mictic mothers from one clonal laboratory population to 20 mg/L Mep (T environment) until the offspring or resting eggs were collected. A parallel control group without Mep (C environment) was also set. Thereafter, offspring from amictic mothers or stem female from resting eggs of mictic mothers were treated similarly in T or C environment. Population growth, life history traits and antioxidant indices of the offspring were examined. The results demonstrated that maternal Mep exposure inhibited population performance of offspring in both life history phases, while the negative effects were markedly buffered in sexual reproduction phase. This study clarifies toxicity of Mep on rotifers and highlights the different response patterns of maternal Mep exposure in different life history phase.
Huahua Gao,Yao Xiao,Juan Hu,Gen Zhang,Peiyuan Qian,Lingli Liu
Dimethoate, a widely used organophosphorus pesticide in agriculture and animal farming, poses significant risks to aquatic ecosystems and human health upon environmental release. Tetracycline, one of the most widely used antibiotics, is frequently detected in surface water and groundwater. In agricultural or urban watersheds, where pesticide runoff and antibiotic-laden wastewater frequently co-occur. The coexistence of tetracycline and dimethoate in nature is common, and this coexistence might impose environmental stress, affecting other organisms. This study investigated the interactive effects of tetracycline (0, 0.085, and 0.85 mg/L) and dimethoate (0, 1.6, and 16 mg/L) on the freshwater rotifer Brachionus calyciflorus , focusing on life cycle parameters, oxidative stress responses, and microbial-mediated dimethoate degradation. Key findings revealed that the co-exposure to tetracycline and dimethoate exerted a synergistic effect, significantly reducing rotifer population density and growth rate compared to exposure to either contaminant alone. Additionally, tetracycline inhibited bacterial growth, which in turn prolonged the environmental persistence of dimethoate in aquatic systems by impeding its natural biodegradation. Collectively, these results highlight the non-additive interactive risks associated with the coexistence of tetracycline and dimethoate, emphasizing the necessity of considering such contaminant interactions in environmental risk assessment to more accurately evaluate the ecological hazards of combined pollution in aquatic systems.
危险品化学品经营许可证（带存储）